1. Field of the Invention
The present invention relates to a control system for a wireless communications terminal used in a wireless communications system, and more specifically, to a control system for a wireless communications terminal in which the control system controlling function states of the wireless communication terminal by using a terminal control device.
2. Description of the Background Art
The use of a wireless communications terminal such as a mobile phone and a PHS (Personal Handy phone System) terminal has spread so rapidly that it is now possible to have a conversation over a telephone or communicate with each other by using such a wireless communications terminal at any time and any place. However, such a desirable advantage of the wireless communications terminal capable of communicating at any time and any place can be undesirable under some circumstances. For example, it is often undesirable for a school lesson to be disturbed by a student's mobile phone ringing in the classroom.
To avoid such situations, the wireless communications terminal, which supports various functions, is structured so as to store, for example, information about whether each function is permitted or not, and/or parameters to be used when executing each function, such that the values of the parameters can be changed from outside of the terminal. Such information stored in the wireless communications terminal is hereinafter referred to as a “function state”. For example, the function state includes information whether calls can be made or received, or information about a type and a sound volume of a ring tone for a received call or mail message, and the like. The wireless communications terminal is typically structured so as to enable the function state to be changed by using input keys or the like, thereby allowing a user of the terminal to change the terminal's function state based on the circumstances where the terminal is used. Thus, the functions of the wireless communications terminal can be restricted within a certain range based on a setting which is inputted by the user.
Japanese Patent Laid-Open Publication No. H10-243454 discloses a system for controlling a function state of a wireless communications terminal based on a method other than using a setting which is inputted by a user. In the system disclosed in this gazette, a terminal control device is placed in an area where a function state of a wireless communications terminal is to be changed. The terminal control device transmits a control signal for changing the function state of the terminal, thereby enabling the terminal to change its function state based on the control signal transmitted from the terminal control device.
However, the above-described system has a problem in that the function states of all wireless communications terminals that have received the control signal will be uniformly changed into the same state, thereby restricting the functions of even those wireless communications terminals whose function states are not to be changed. Furthermore, the terminal control device cannot check whether a wireless communications terminal has actually changed its function state, which makes it impossible for the device to manage the function state of the terminal based on the current function state thereof.